Directly below is the plan view of the no. 22 chassis from the 1947 BSA parts list book. Underneath that, is an artist's sketch showing the chassis in three dimensions, taken from Jo Axon's book, "Our Sidecars". Interestingly, it shows a single spring at the front, rather than the two shown in the first diagram. My own example has two springs, as shown in the BSA parts list view.